The OpenCPN project Linux packaging options includes:
Although there are exceptions the community's ambition is to build plugins for all of these platforms.
What's described here is the different ways to install OpenCPN using packages from the project. Other options includes downstream packages for some distros and integrated navigation packages with various software and hardware like https://openmarine.net/openplotter
The opencpn package is from version 20.04 Focal included in the Ubuntu repositories and can be installed directly using command line (apt) or GUI tools like Gnome Software. However, in many situations (including the time of writing) this version lags the upstream release with a year or more. In order to get a more recent release first install the Ubuntu PPA as desrcibed in Ubuntu PPA before installing OpenCPN
Note that the opencpn package only is available for LTS releases. For other releases, use the Flatpak packaging (below).
The opencpn package is included in Debian since version 11 (Bullseye) and can be installed as other programs using the command line (apt) or GUI tools like Gnome Software. Note that while this package is available on 16 different architectures (!), plugin support is only available for amd64,
Other distributions, including Ubuntu non-LTS releases, are supported by Flatpak. See Flatpak for instructions.
Flatpak is a somewhat new way of distributing packages which runs on basically all linux distributions. The Flatpak packages have been tested during the 5.2.0 cycle. To summarize, there is no performance hit compared to native packages. The compatibility with various distributions is also good. However, there are large downloads involved, especially if OpenCPN is the only Flatpak application on the system.
For Raspberrry Pie (RPi) 3 the official Raspbian OS is supported. OpenCPN can be installed after adding the Ubuntu PPA as described in Raspberry Pi 2/3]]
RPi - 4 typically runs various aarch64 OS:s like the Raspbian Beta, vanilla Debian, Ubuntu or Fedora. The supported packaging for this eco-system is Flatpak, which runs on all of these OS:es. See Flatpak for instructions, they are identical to those for amd64/x86_64 systems.